(1) Field of the Invention
The invention relates to the fabrication of integrated circuit devices and more particularly, to a procedure for the correct and well controlled processing of batches or lots of semiconductor devices.
(2) Description of the Prior Art
The fabrication of semiconductor devices requires not only advanced equipment that is used to execute processing steps that are of a most advanced and advantageous nature, it also requires that the processing steps are scheduled in a precise and well-controlled manner. Most modern semiconductor manufacturing facilities have long since converted to systems that are computer controlled, whereby every step of the manufacturing process is scheduled and executed under the control of sophisticated support software. Such systems are known in the industry under a range of acronyms. Some of these acronyms have practically become industry standards and are marketed as individual support packages to control major sections of a semiconductor manufacturing facility. Other software support packages are in house designs that may or may not have proven to live up to high levels of expectations of control and efficiency of operation. Many of these software programs are of an extremely sophisticated nature and are used for instance for high speed product testing. Other software support packages are available for controlling processing parameters while the various processing steps that are required to create semiconductor devices are being executed. One problem with the latter equipment is that it is often very difficult to predict and to therefore control the impact that various processing conditions have on the actual processes that are being performed while this lack of insight is exacerbated by the lack of insight in the inter-reaction and inter-dependence of many of the processing parameters and environmental conditions.
Where many of the available and implemented software packages address product manufacturing or product testing, that is the physical behavior of the product either during production or after is has been completed, there also exists a wide body of support software that concerns itself with scheduling and control of the product while it is being manufactured. These software packages are in the broadest scope known as Management Information Support (MIS) packages. These programs in the strict sense control the flow of the product through the manufacturing line. This is in most cases however not the limit of the functions of these programs. The limited scope of this software can readily be extended to the point where the flow of the product is connected with and has an impact on product scheduling, yield analysis, financial and cost analysis and a host of other inter-related disciplines that all provide better insight and control in managing a modern semiconductor manufacturing operation.
The centralized control of these packages in many cases results in large databases that contain related information. For instance, many of the support software programs that are implemented in a semiconductor facility are aimed at and dedicated to the numerical control of production equipment. The equipment may of a specific type, such as an etch or plasma chamber, or it may be a high speed tester that is dedicated to testing a variety of devices and whereby the test data is contained on the separate database from where it is loaded to the tester upon request by the tester. All of this under software control and without the help of human intervention. An important feature of equipment control is that the equipment provides status and progress information to its supporting software, this information can in turn be used to for instance re-schedule production runs on a piece of equipment or to conclude from test results that a condition exist in the manufacturing steps that requires human intervention. Where this support software is typically very sophisticated and autonomous, it is in most cases still required that human intervention can be exercised. For instance, initial scheduling of a batch lot processing is typically done via terminal where an operator inputs the required parameters. These parameters can be lot numbers, part numbers, specific test requirements, environmental processing parameters for a particular piece of equipment, etc. There also may be a broad separation of types of equipment that are being used. Most equipment in a manufacturing facility is aimed at producing product. It is thereby however also feasible that computer-controlled equipment is aimed at Research and Development (RandD) functions. The requirements that are typically placed on the latter type of equipment may well differ considerably form the requirements that are placed on production equipment even though the technical capability of both types of equipment may be the same.
One of the major problems that is frequently experienced when using computer controlled equipment is human error. Where data is entered by human intervention, there is always the possibility that errors are made and entered into the system. These errors can be very costly and can also be very difficult to detect. It is clear that the best way to enter data into a computer system is to have some way of validating the entered data at the time that the data is entered. The basic method that is used to perform this validation should, ideally, not require human intervention. It should be a validation whereby the data that is entered is, whenever possible, validated against reference data. This data is frequently referred to as golden data in the sense that this data represents the uncontested correct information.
The invention addresses problems of data integrity of equipment data that is contained within and managed by a computer-controlled system.
A principle objective of the invention is to assure that data that is used by semiconductor processing equipment is correct and uncorrupted.
It is another objective of the invention to provide a data repository for a computer controlled system that contains valid reference data for equipment scheduling and operation.
Another objective of the invention is to eliminate human error from data that is entered into a system where semiconductor equipment is under computer control.
Yet another objective of the invention is to prevent data corruption of data that is stored on computer controlled databases.
A still further objective of the invention is to prevent the scrapping of product as a result of incorrect data that is stored on a computer controlled system.
In accordance with the objectives of the invention a new method is provided to enter data into a computer controlled equipment control system. The data that are entered into the system by human intervention are validated against a reference database. The reference database contains only data that is certified and correct. Any errors that may have been created as part of the process of human entry of the data will therefore be identified and can be eliminated.